Scientists and government officials are gathered this week in Yokohama, Japan, to agree on the exact wording of a final summary of the UN report – seen as the authoritative account of climate change science – before its release on Monday.

Britain and other governments have been severely critical of a finding from Richard Tol, a Dutch economics professor at Sussex University, according to documents made available to the Guardian.

Britain and other governments rejected the finding as an underestimate when the draft was first circulated to officials last December, noting that Tol did not include the potential for catastrophic damages due to climate change. "This statement … risks being deeply misleading," British officials wrote.

The US and other countries have seen a rise in the number of extreme weather events such as hurricanes and flooding costing more than $1bn. "It seems reasonable to conclude that the quoted figures of 0.2% to 2% are at best an underestimate, and at worst completely meaningless," the officials wrote.

Other governments, including Belgium, Norway and the US, also took issue with Tol's estimate of potential climate losses. France said: "Its message is unclear and is not widely accepted by the community." Japan suggested the line carry a lengthy clarification or be struck off completely.

The effort of distilling 30 long and detailed scientific chapters into a 40-page summary is often contentious. This week's session is closed to reporters, and governments do not make public their comments on the draft.

By early on Friday, after days of wrangling, the meeting had signed off on only a few sections of the densely worded summary, and had demanded changes to a number of complicated graphics.

Tol said he was unconcerned about the criticism. "The UK government is just worried about embarrassment," he said. "They perhaps feel now a little embarrassed that the official estimate of the UK government conflicts with the official estimate that may come out of the United Nations."

However, he acknowledged that his finding may not make it through the review process.

Tol caused a controversy in Yokahama this week when he went public about his disagreements with other authors of the UN report. He said he pulled out of the team writing the summary last October because the UN report was too alarmist about the effects of climate change. However, he still came to Yokohama to help with his section, on economics, and the final draft of the summary.

"It just felt that it was drifting in the wrong direction, and I wasn't comfortable being associated with it," Tol said. "The almost exclusive attention to risks and the over-emphasis on impacts – I don't think that's the right message we want to bring across," he said.